Date sent by sender

In Email module (Inbox Tab) Date sent by sender column showing date and time which is inserted in Email_cache table or (Mail Received date and time) .When i clicked on check email button.but what i want it need to be show the exact date and time when the sender sent the email.which is showing in the (My sent Email Tab) Date sent by sender column from sender login

for example

if user A sent an email to user B

so in My sent Email Tab of user A tab the date and time showing exactly when the mail sent (25-12-2014 09 :00 AM )

User B clicked on Check Email Button on the same day 04:00 PM so in the (Inbox Tab) Date sent by sender column showing (25-12-2014 04 :00 PM ) and i want it need to be show (25-12-2014 09 :00 AM ) in the (Inbox Tab) Date sent by sender column to..